ATM products slowly infiltrate data communications applications

ATM products slowly infiltrate data communications applications

To solve the bottleneck problems of moving more data at higher transmission speeds, equipment suppliers are turning to fiber-optic and ATM networking technologies

paul korzeniowski

Data communications users` insatiable need for more-powerful networks is expected to spark sales of fiber-optic cables and equipment. In their attempt to move more information at higher speeds over copper-based networks, computer users are discovering transmission congestion bottlenecks in the backbone, server and desktop. To solve these problems, equipment suppliers are investigating higher-speed networking options, especially those implementing fiber-optic and asynchronous transfer mode technologies.

In fact, ATM technology was specifically designed to solve these problems. It supports a range of transmissions speeds from 1.5 to 622 megabits per second. With this approach, companies will no longer have to rip out their network infrastructure to boost transmission speeds.

Another advantage is that ATM operates on both local and wide area networks. Because routers and translation devices are no longer needed to move from a LAN to a WAN with ATM, companies can more easily manage their networks.

ATM also works with a variety of signal transmission types, including data, video and voice. Wade Appelman, director of advanced product technologies at Cabletron Systems Inc., Rochester, NH, expects growing interest in emerging network applications--World Wide Web browsers, multicast video transmissions and Powerpoint graphic applications--to fuel ATM equipment and related fiber-optic cable sales. "Seventy-five percent of our customers use fiber for their backbone networks," notes Appelman.

Although its potential appears vast, ATM`s demonstrated capabilities have been limited so far. "Companies are installing test beds to determine what benefits ATM offers them," says Robert Marshall, product marketing manager at Interphase Inc., a Dallas, TX, supplier of ATM chipsets.

Currently, few data communications suppliers are delivering ATM products. Fore Systems Inc., a Warrendale, PA, data communications supplier that has emerged as the early market leader, has seen its revenues skyrocket from $1 million in 1992 to $75.6 million in 1994. The company reports that ATM technology has been used to solve backbone- and server-congestion problems. "Companies are hooking workstations together in a server cluster and getting supercomputer performance out of Unix workstations," maintains George Prodan, director of adapter marketing at Fore Systems.

To make a major impact on the market, though, ATM technology has to make its way to the desktop, and that journey has begun. Prodan says that the number of Fore`s ATM adapters sold jumped from 1200 in 1993 to 5680 in 1994. Although this growth is notable, the numbers pale in comparison to the millions of Ethernet adapters sold every month. Ethernet products have made their way to the mass market, which means installation into personal computers. The bulk of ATM adapters work with high-end workstations, such as those made by Sun Microsystems Inc.

This situation is changing, however. Suppliers such as Fore and Interphase have developed PC network interface cards. ATM support is spreading as data communications suppliers scramble to add ATM capabilities to their product lines. Leading network equipment vendors, such as Bay Networks, Cabletron, Cisco Systems Inc. and IBM, have all outlined plans to deliver ATM equipment during 1995.

Furthermore, by the end of this year, Chipcom Corp., Digital Equipment Corp. and Hewlett-Packard Co. all plan to deliver ATM wares. Also, major telecommunications carriers, including Ameritech Corp., AT&T, MCI and Sprint, have outlined plans to deliver ATM services. "There seems no doubt that ATM will emerge as a key networking technology," states David Flynn, the high-speed product line manager at 3Com Corp., a Santa Clara, CA, data communications supplier. "The debate centers on when it will reach the desktop."

Fore Systems anticipates a big ATM swing to the desktop during 1996. "Companies have completed their pilot programs and are ready to move to wide-scale ATM deployment," according to Prodan.

Cabletron is more cautious. "Technologies often evolve slower than the initial hype," argues Appelton. "So, I don`t think many users will be working with desktop ATM connections for at least another two to three years."

Whether it takes 12 or 36 months, the eventual migration should spur huge increases in fiber-optic equipment sales. Until early this year, fiber was the only ATM medium, but copper wiring refuses to concede. Prodan estimates the ratio of fiber-optic to copper products at 70/30 and says, "The ratio could dip to a 60/40 split as technologies such as 25-Mbit/sec ATM emerge. I do expect that a lot more users than there are now will have fiber at their desktops in a few years."

Infrastructure changes

Accordingly, corporations are undertaking major infrastructure changes to install higher-speed networks. "Many companies are examining how to provide their users with more bandwidth," notes Prodan. The upgrade path to higher speed networks, though, is littered with obstacles. Moving from an Ethernet network to a fiber distributed data interface network, for example, requires that a company swap out all its network adapter cards, wiring hub connections and management software.

Another problem arises when companies separate their networks into distinct segments. Generally, companies use one set of tools to manage their Ethernet LANs and a second set to oversee their WANs.

Another problem emerges because most copper-based network technologies are not suited to emerging communications applications. Networking technologies such as Ethernet were designed to carry data and, therefore, must be radically altered to transport video or voice information.

The most serious problems, however, focus on bottlenecks in backbone network, client/server and desktop connections. For most data applications, backbone networks are used to transmit information from a LAN in one department to a LAN in another department. In client/server data communications applications, groups of users access information stored on central servers. As the number of users accessing a server increases, so does the amount of information pumped to and from the server. Consequently, a backbone network might not have sufficient bandwidth to move information to all users.

In installing servers, users have preferred switching-based networks, which provide dedicated connections from one device to another. Desktop congestion occurs in these networks, however, when users work with complex applications transmitting high data rates. Currently, desktop congestion is more common with engineering and scientific applications rather than with daily business systems.

Fiber competition

As ATM products make their way to market, corporations must decide whether to upgrade from copper wiring to fiber-optic cables to support higher-speed networks. Copper wiring has been the most popular choice for Ethernet and token ring LANs because of its perceived low cost, wide availability and easy installation.

The main competition to ATM technology comes from Fast Ethernet, a scheme to increase Ethernet`s 10-Mbit/sec transmission to 100 Mbits/sec. Fast Ethernet is designed to run over copper wiring, so the switch from Ethernet should be straightforward.

Ethernet gained market popularity because of its low price. Ethernet cards sell for as low as $75 per user compared to $250 or more for alternatives, such as token ring LAN cards. At $350 per user, Fast Ethernet cards cost half as much as ATM or FDDI adapter cards.

But there are impediments to Fast Ethernet. Vendors have split into two camps and are promoting competing standards. One group, which includes Bay Networks, Sun Microsystems and 3Com, backs the 100Base-X specification, which is similar to Ethernet. A second group, which includes Hewlett-Packard and IBM, supports 100VG-AnyLAN, a scheme that works with token ring LANs and Ethernet.

Furthermore, the ATM versus Fast Ethernet competition is not evolving as a copper wire versus fiber-optic cable decision. Last year, a group of vendors led by IBM began working on a 25-Mbit/sec version of ATM designed to run on copper wiring. The ATM Forum, an ad hoc vendor consortium, blessed the standard at the end of 1994, and vendors expect to deliver 25-Mbit/sec ATM products by the end of this year.

How interested users will be in all these wares is unclear. Rick Malone, a principal at Vertical Systems Group Inc., a Dedham, MA, consulting company, asks, "Why would a company move to 25-Mbit/sec ATM? It would have to swap out its adapter cards, wiring hub ports and management software. The technology offers only an incremental benefit compared to 16-Mbit/sec token-ring LANs. If a company has to do all that work, it should expect a huge increase, say 155 Mbits/sec of bandwidth."

Furthermore, says 3Com`s Flynn, 25-Mbit/sec ATM adapters are more expensive and complex than alternatives, such as switched Ethernet. "Customers may look at 25-Mbit/sec ATM, but I don`t think they will see much incentive to switch to it."

Fiber now

Many companies are ready for network overhaul. These companies installed their LANs in the late 1980s, so their networks are near the end of their life cycles. "Corporations will need an infrastructure capable of supporting their information needs into the next century," states Prodan, "so why not go ahead and install fiber now rather than later?" Fiber is secure, carries information longer distances and has more long-term installation potential than copper.

Traditionally, fiber-optic cabling has been more expensive than copper wiring, but the gap is narrowing, as seen in the price of ATM cards. Interphase sells PC-copper ATM cards for $650, compared to $850 for fiber-optic cards; S-bus copper adapters cost $1050, compared to $1250 for fiber-optic versions.

ATM equipment prices are still too high to encourage widespread desktop usage. But suppliers expect ATM cards prices to drop quickly. Vernon Little, manager for LAN products at PMC-Sierra Inc., a components supplier in Vancouver, BC, Canada, advises that a vendor invests approximately $100 to manufacture an ATM card. One reason for the high price is that these cards are populated with 15 to 20 integrated circuit chips. He anticipates component manufacturers to improve their integrated circuit processes and expects prices to drop by 10% to 15% by the end of this year.

Another issue concerns leading adapter-card suppliers, including Intel Corp. and 3Com Corp. These corporations have not yet moved into the ATM market. Instead, they have been more interested in Fast Ethernet products. 3Com`s Flynn expects sales of desktop Fast Ethernet products to be much higher than ATM products during the next few years. But the company is not ignoring the ATM market. 3Com started shipment of ATM adapters for S-bus computers and PCs during this past summer.

Acceptance hurdles

In addition to relatively high prices, ATM technology must overcome other hurdles to gain widespread desktop acceptance. One constraint is the technology`s immaturity.

Cabletron`s Appelman advises that earlier this year the ATM Forum completed work on LAN emulation capabilities, which enable Ethernet and token ring data streams to run over ATM networks. "Companies will not install ATM equipment unless they are able to integrate it with existing equipment," he states. In addition to LAN emulation, more work is needed on network management issues. For example, the issue of how to pass management information from one ATM network to another has to be resolved.

Because most companies have heterogeneous networking equipment, they are leery of moving to ATM. Bay Networks, however, has delivered a product that connects Ethernet LANs to ATM networks, and other vendors are expected to follow suit during the coming months.

Transmission jitter control

Another hurdle to overcome is transmission jitter control. This problem is an issue for top-speed ATM networks because error-checking routines are not yet available. "Right now, there is no jitter specification for 622-Mbit/sec LANs, so vendors are staying away from the development of such products," remarks Little at PMC-Sierra.

Although outstanding issues need to be addressed, positive market signs have emerged. Vendors are finding clever ways to make fiber-optic cabling a more attractive medium. Earlier this year, NEC Ltd. proposed using plastic fiber-optic cable for ATM transmission. PMC-Sierra`s Little declares that plastic fiber would be less expensive and easier to install than current glass fiber.

Until ATM technology asserts its attributes, FDDI technology, which supports transmission speeds to 150 Mbits/sec, reigns as the most popular signal transmission technology over fiber backbone networks. Available since the late 1980s, FDDI has achieved maturity, and companies are comfortable using FDDI for important data communications applications.

This standard technology implements a redundant dual-ring architecture, which ensures reliability. This feature is important because backbone networks carry multiple megabits of information, and problems can knock out departmental LANs. In addition, fiber is less susceptible to security breaks than copper wiring.

Many industry analysts predicted that FDDI would emerge as a key desktop communications technology, but that did not happen because of cost. Fiber FDDI connections cost between $1000 and $2500, which is more than 10 times higher than the cost of Ethernet connections--now the most popular desktop connection.

Copper FDDI connections, which bring the cost below $1000, have not been popular either. "Companies are hesitant to move to a new networking technology simply to boost transmission speeds," explains Malone at Vertical Systems. "The change means swapping out existing infrastructure and teaching technicians a new technology. So far, vendors have not been able to prove that the benefits from higher-speed technologies are worth the headaches."

Consequently, fiber gained the most acceptance in the smallest of the three congestion spots--the backbone. Many data communications suppliers focused on the two larger spots--server and desktop--but in these areas fiber developed the reputation of an expensive medium. "A lot of vendors have ignored fiber, and that has helped us keep our sales growing," states Cabletron`s Appelman. He claims that FDDI sales have been increasing at a rate of approximately 100% per year and have enabled the company to slash the price of its FDDI concentrator from $40,000 to $19,000 earlier this year.

3Com`s Flynn adds, "Those predicting the demise of FDDI haven`t come close to being correct. Sales of our FDDI products increased by 300% during the last fiscal year." u

Paul Korzeniowski is a freelance writer based in Malden, MA, and specializing in networking issues.

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